Drug-induced cholestasis

Rodent models of cholestatic liver disease: A practical guide for translational research

Cholestatic liver disease denotes any situation associated with impaired bile flow concomitant with a noxious bile acid accumulation in the liver and/or systemic circulation. Cholestatic liver disease can be subdivided into different types according to its clinical phenotype, such as biliary atresia, drug-induced cholestasis, gallstone liver disease, intrahepatic cholestasis of pregnancy, primary biliary cholangitis and primary sclerosing cholangitis. Considerable effort has been devoted to elucidating underlying mechanisms of cholestatic liver injuries and explore novel therapeutic and diagnostic strategies using animal models. Animal models employed according to their appropriate applicability domain herein play a crucial role. This review provides an overview of currently available in vivo animal models, fit-for-purpose in modelling different types of cholestatic liver diseases. Moreover, a practical guide and workflow is provided which can be used for translational research purposes, including all advantages and disadvantages of currently available in vivo animal models.

Application of Impedance-Based Techniques in Hepatology Research

There are a variety of end-point assays and techniques available to monitor hepatic cell cultures and study toxicity within in vitro models. These commonly focus on one aspect of cell metabolism and are often destructive to cells. Impedance-based cellular assays (IBCAs) assess biological functions of cell populations in real-time by measuring electrical impedance, which is the resistance to alternating current caused by the dielectric properties of proliferating of cells. While the uses of IBCA have been widely reported for a number of tissues, specific uses in the study of hepatic cell cultures have not been reported to date. IBCA monitors cellular behaviour throughout experimentation non-invasively without labelling or damage to cell cultures. The data extrapolated from IBCA can be correlated to biological events happening within the cell and therefore may inform drug toxicity studies or other applications within hepatic research. Because tight junctions comprise the blood/biliary barrier in hepatocytes, there are major consequences when these junctions are disrupted, as many pathologies centre around the bile canaliculi and flow of bile out of the liver. The application of IBCA in hepatology provides a unique opportunity to assess cellular polarity and patency of tight junctions, vital to maintaining normal hepatic function. Here, we describe how IBCAs have been applied to measuring the effect of viral infection, drug toxicity /IC50, cholangiopathies, cancer metastasis and monitoring of the gut-liver axis. We also highlight key areas of research where IBCAs could be used in future applications within the field of hepatology.

FGF21 acts as a negative regulator of bile acid synthesis

Fibroblast growth factor 21 (FGF21) is a potent regulator of glucose and lipid homeostasis in vivo; its most closely related subfamily member, FGF19, is known to be a critical negative regulator of bile acid synthesis. To delineate whether FGF21 also plays a functional role in bile acid metabolism, we evaluated the effects of short- and long-term exposure to native FGF21 and long-acting FGF21 analogs on hepatic signal transduction, gene expression and enterohepatic bile acid levels in primary hepatocytes and in rodent and monkey models. FGF21 acutely induced ERK phosphorylation and inhibited Cyp7A1 mRNA expression in primary hepatocytes and in different rodent models, although less potently than recombinant human FGF19. Long-term administration of FGF21 in mice fed a standard chow diet resulted in a 50-60% decrease in bile acid levels in the liver and small intestines and consequently a 60% reduction of bile acid pool size. In parallel, colonic and fecal bile acid was decreased, whereas fecal cholesterol and fatty acid excretions were elevated. The long-acting FGF21 analog showed superiority to recombinant human FGF21 and FGF19 in decreasing bile acid levels with long duration of effect action in mice. Long-term administration of the long-acting FGF21 analogs in obese cynomolgus monkeys suppressed plasma total bile acid and 7α-hydroxy-4-cholesten-3-one levels, a biomarker for bile acid synthesis. Collectively, these data reveal a previously unidentified role of FGF21 in bile acid metabolism as a negative regulator of bile acid synthesis.

Biliary excretion of pravastatin and taurocholate in rats with bile salt export pump (Bsep) impairment

The bile salt export pump (BSEP) is expressed on the canalicular membrane of hepatocytes regulating liver bile salt excretion, and impairment of BSEP function may lead to cholestasis in humans. This study explored drug biliary excretion, as well as serum chemistry, individual bile acid concentrations and liver transporter expressions, in the SAGE Bsep knockout (KO) rat model. It was observed that the Bsep protein in KO rats was decreased to 15% of that in the wild type (WT), as quantified using LC-MS/MS. While the levels of Ntcp and Mrp2 were not significantly altered, Mrp3 expression increased and Oatp1a1 decreased in KO animals. Compared with the WT rats, the KO rats had similar serum chemistry and showed normal liver transaminases. Although the total plasma bile salts and bile flow were not significantly changed in Bsep KO rats, individual bile acids in plasma and liver demonstrated variable changes, indicating the impact of Bsep KO. Following an intravenous dose of deuterium labeled taurocholic acid (D4-TCA, 2 mg/kg), the D4-TCA plasma exposure was higher and bile excretion was delayed by approximately 0.5 h in the KO rats. No differences were observed for the pravastatin plasma concentration-time profile or the biliary excretion after intravenous administration (1 mg/kg). Collectively, the results revealed that these rats have significantly lower Bsep expression, therefore affecting the biliary excretion of endogenous bile acids and Bsep substrates. However, these rats are able to maintain a relatively normal liver function through the remaining Bsep protein and via the regulation of other transporters. Copyright © 2016 John Wiley & Sons, Ltd.

Inhibition of bile salt transport by drugs associated with liver injury in primary hepatocytes from human, monkey, dog, rat, and mouse

Interference of bile salt transport is one of the underlying mechanisms for drug-induced liver injury (DILI). We developed a novel bile salt transport activity assay involving in situ biosynthesis of bile salts from their precursors in primary human, monkey, dog, rat, and mouse hepatocytes in suspension as well as LC-MS/MS determination of extracellular bile salts transported out of hepatocytes. Glycine- and taurine-conjugated bile acids were rapidly formed in hepatocytes and effectively transported into the extracellular medium. The bile salt formation and transport activities were time‒ and bile-acid-concentration‒dependent in primary human hepatocytes. The transport activity was inhibited by the bile salt export pump (BSEP) inhibitors ketoconazole, saquinavir, cyclosporine, and troglitazone. The assay was used to test 86 drugs for their potential to inhibit bile salt transport activity in human hepatocytes, which included 35 drugs associated with severe DILI (sDILI) and 51 with non-severe DILI (non-sDILI). Approximately 60% of the sDILI drugs showed potent inhibition (with IC50 values <50 μM), but only about 20% of the non-sDILI drugs showed this strength of inhibition in primary human hepatocytes and these drugs are associated only with cholestatic and mixed hepatocellular cholestatic (mixed) injuries. The sDILI drugs, which did not show substantial inhibition of bile salt transport activity, are likely to be associated with immune-mediated liver injury. Twenty-four drugs were also tested in monkey, dog, rat and mouse hepatocytes. Species differences in potency were observed with mouse being less sensitive than other species to inhibition of bile salt transport. In summary, a novel assay has been developed using hepatocytes in suspension from human and animal species that can be used to assess the potential for drugs and/or drug-derived metabolites to inhibit bile salt transport and/or formation activity. Drugs causing sDILI, except those by immune-mediated mechanism, are highly associated with potent inhibition of bile salt transport.

Acute cholestatic liver injury caused by polyhexamethyleneguanidine hydrochloride admixed to ethyl alcohol

INTRODUCTION

Polyhexamethyleneguanidine hydrochloride (PHMG) is an antimicrobial biocide of the guanidine family. In the period from August 2006 to May 2007, more than 12500 patients were admitted to hospital with a history of drinking illegal cheap "vodka" in 44 different regions in Russia, of whom 9.4% died. In reality, the "vodka" was an antiseptic liquid composed of ethanol (≈93%), diethyl phthalate, and 0.1-0.14% PHMG (brand name "Extrasept-1").

MATERIAL AND METHODS

We performed an analysis of the clinical features and outcome in four poisoning treatment centers in the cities of Perm, Ekaterinburg, Irkutsk, and Khabarovsk. A total of 579 patients (215 females and 364 males) with similar symptoms were included.

RESULTS

The main symptoms on admission included jaundice (99.7%), skin itch (78.4%), weakness (96%), anorexia (65.8%), dizziness (65.3%), nausea (54.8%), vomiting (22.6%), stomach ache (52.7%), diarrhea (32%), and fever (50%). Mild symptoms were found in 2.5% of cases, moderate in 63%, and severe in 34.5%. Laboratory results were (mean ± SD): total bilirubin 249 ± 158 μmol/L, direct bilirubin 166 ± 97 μmol/L, cholesterol 14 ± 8 mmol/L, alanine aminotransferase 207 ± 174 IU/L, aspartate aminotransferase 174 ± 230 IU/L, alkaline phosphatase 742 ± 751 IU/L, and gamma-glutamyltranspeptidase 1199 ± 1095 IU/L. Patients generally recovered over a period of 1-5 months, although high levels of alkaline phosphatase and gamma-glutamyltranspeptidase were still found in all patients examined after 6 months. Sixty-one patients (10.5%) died between 23 and 150 days after poisoning. Local cholestasis, inflammatory infiltration, and fibrosis developing into cirrhosis were found by liver biopsy.

CONCLUSION

Acute liver injury caused by PHMG-hydrochloride or PHMG in combination with either ethanol or diethyl phthalate can be characterized as cholestatic hepatitis with a severe inflammatory component causing high mortality.

Postmortem analyses unveil the poor efficacy of decontamination, anti-inflammatory and immunosuppressive therapies in paraquat human intoxications

Background

Fatalities resulting from paraquat (PQ) self-poisonings represent a major burden of this herbicide. Specific therapeutic approaches have been followed to interrupt its toxic pathway, namely decontamination measures to prevent PQ absorption and to increase its excretion from organism, as well as the administration of anti-inflammatory and immunosuppressive drugs. Until now, none of the postmortem studies resulting from human PQ poisonings have assessed the relationship of these therapeutic measures with PQ toxicokinetics and related histopathological lesions, these being the aims of the present study.

Methodology/Principal Findings

For that purpose, during 2008, we collected human fluids and tissues from five forensic autopsies following fatal PQ poisonings. PQ levels were measured by gas chromatography-ion trap mass spectrometry. Structural inflammatory lesions were evaluated by histological and immunohistochemistry analysis. The samples of cardiac blood, urine, gastric and duodenal wall, liver, lung, kidney, heart and diaphragm, showed quantifiable levels of PQ even at 6 days post-intoxication. Structural analysis showed diffused necrotic areas, intense macrophage activation and leukocyte infiltration in all analyzed tissues. By immunohistochemistry it was possible to observe a strong nuclear factor kappa-B (NF-κB) activation and excessive collagen deposition.

Conclusions/Significance

Considering the observed PQ levels in all analyzed tissues and the expressive inflammatory reaction that ultimately leads to fibrosis, we conclude that the therapeutic protocol usually performed needs to be reviewed, in order to increase the efficacy of PQ elimination from the body as well as to diminish the inflammatory process.

Prolonged cholestasis associated with short-term use of celecoxib

Drug-induced liver injury due to celecoxib, a first generation Cox-2 inhibitor, has been rarely reported. We describe one case of severe and prolonged cholestasis after treatment with celecoxib for 12 days in a young woman with no evidence of other causes of liver disease or allergy. Jaundice lasted for 3 months, pruritus and abnormal liver biochemistry persisted for 18 months after stopping the drug. Liver biopsy specimens showed a cholestatic pattern of liver injury with only minimal mononuclear infiltrate in the portal tracts. This case report supports the notion that celecoxib may cause bland, long term cholestasis.

Isolated idiopathic bile ductular hyperplasia in patients with persistently abnormal liver function tests

BACKGROUND/AIMS

In routine examination of liver biopsies isolated ductular hyperplasia (IDH) may be the only histopathological change. Here we describe the clinical and immunophenotypic features of a number of cases retrospectively identified reviewing consecutive liver biopsies from five Italian centers over 4 years.

METHODS

We reviewed 1235 cases biopsied for chronic liver disease (1078 for viral hepatitis). Records of cases fulfilling the inclusion criteria for IDH were reviewed to identify possible aetiologies. Biopsies showing IDH and control biopsies were studied by immunohistochemistry for cytokeratin-7, epithelial-membrane-antigen (EMA), neural-cell-adhesion-molecule (NCAM), Ki-67.

RESULTS

Out of 70 biopsies fulfilling IDH criteria, 16 (22.8%) were of unknown aetiology. Patients with idiopathic IDH (age 38.2+/-11 years) were asymptomatic with mild, long-lasting ALT and/or gammaGT increases. A significant increase of well-differentiated (EMA-positive; NCAM-negative) bile ductules localized at the portal interface and inside the lobule was found in idiopathic IDH.

CONCLUSIONS

Idiopathic IDH was present in 10% of adults biopsied for persistent mild liver function test abnormalities unrelated to viral hepatitis. In contrast with the ductular reaction seen in many forms of liver disease, it is characterized by well-differentiated hyperplastic ductules in absence of significant inflammation, and may represent a non-specific pattern of reaction to mild liver damages.

Drug- and chemical-induced cholestasis

Cholestasis caused by medicinal and chemical agents is an increasingly well-recognized cause of liver disease. Clinical drug-induced cholestatic syndromes producing jaundice and bile duct injury can mimic extrahepatic biliary obstruction, primary biliary cirrhosis, and sclerosing cholangitis, among others. This article updates the various forms of drug-induced cholestasis, focusing on the clinicopathologic features of this form of hepatic injury and on the known or putative mechanisms by which drugs and chemicals lead to cholestasis.

Deformed liver with prominent proliferation of bile ducts in a pig

A deformed liver characterized by remarkable ductular proliferation was encountered in a 6-month-old pig and examined histopathologically. The most conspicuous histopathologic change was a mild to severe ductular proliferation in the interlobular areas without any degenerative changes of cholangiolar epithelial cells or hepatocytes. Fibrotic changes and reconstruction of the lobule were not found. Morphological evidence of intrahepatic and extrahepatic cholestasis was lacking. Other characteristics were deformity with displacement of the gall bladder, irregular shape and size of lobules, and structural abnormality of large-sized vessels. The severe ductular proliferation was considered to be due to structural malformations of the excretion channel of bile.

Terbinafine-induced hepatic dysfunction

A 41-year-old man developed severe hepatic dysfunction following a 3.5-week course of terbinafine (250 mg/day). He suffered marked pruritus, jaundice, malaise, anorexia and loin pain. Serum bilirubin rose to a peak value of 718 micromol/l with alkaline phosphatase at 569 U/l, alanine aminotransferase at 90 U/l, aspartate aminotransferase at 63 U/l and a prolonged prothrombin time of 21 s, unresponsive to vitamin K. Transjugular liver biopsy showed canalicular cholestasis consistent with a drug reaction. Symptoms resolved 11 months after drug cessation, with liver function tests returning to normal values after 15 months. This case represents the most severe cholestatic reaction reported to date, resulting in patient recovery without liver transplantation. A comprehensive literature review is provided.

Prolonged cholestasis after acute paraquat poisoning through skin absorption

Ingestion of paraquat is the most common cause of fatal pesticide poisoning. Liver involvement in acute paraquat poisoning is self-limited and usually consists of cholestasis. However, long-term hepatic effects after paraquat exposition have not been described up to now, probably because of the high mortality rate of this acute poisoning. We report the case of an agricultural worker who developed persistent cholestasis after an episode of acute paraquat poisoning through skin absorption.

Drug-induced liver diseases

Drug-induced liver injuries make up a persisting and challenging problem for physicians, health agencies and pharmaceutical firms. The clinical expression is polymorphous, acute hepatitis being predominant. The diagnosis is frequently difficult because of the absence of specific signs in most cases and mainly relies on the exclusion of other causes. The diagnosis should be particularly evoked in patients over 50 yr who are taking many drugs, after viral infections have been ruled out. Acute hepatocellular hepatitis is particularly severe because of the risk of fulminant hepatitis or of a more insidious course leading to cirrhosis. Cross hepatotoxicity can sometimes occur. One should avoid re-administration of not only the causative agents but also of other drugs belonging to the same family or having a related chemical structure. The prediction of the hepatotoxicity of new drugs must be improved. Investigations would be particularly useful for drugs having critical chemical structures and belonging to families with an established history of hepatotoxicity.

Drug- and estrogen-induced cholestasis through inhibition of the hepatocellular bile salt export pump (Bsep) of rat liver

BACKGROUND & AIMS

Drug-induced cholestasis is a frequent form of acquired liver disease. To elucidate the molecular pathogenesis of drug-induced cholestasis, we investigated the effects of prototypic cholestatic drugs on the canalicular bile salt export pump (Bsep) of rat liver.

METHODS

Vesicles were isolated from Bsep-, Mrp2-, and Bsep/Mrp2-expressing Sf9 cells. Canalicular plasma membrane (cLPM) vesicles from rat liver and Sf9 cell vesicles were used to study adenosine triphosphate (ATP)-dependent solute uptake by a rapid filtration technique.

RESULTS

Bsep-expressing Sf9 cell vesicles showed ATP-dependent transport of numerous monoanionic bile salts with similar Michaelis constant values as in cLPM vesicles, whereas several known substrates of the multispecific organic anion transporter Mrp2 were not transported by Bsep. Cyclosporin A, rifamycin SV, rifampicin, and glibenclamide cis-inhibited Bsep-mediated bile salt transport to similar extents as ATP-dependent taurocholate transport in cLPM vesicles. In contrast, the cholestatic estrogen metabolite estradiol-17beta-glucuronide inhibited ATP-dependent taurocholate transport only in normal cLPM and in Bsep/Mrp2-coexpressing Sf9 cell vesicles, but not in Mrp2-deficient cLPM or in selectively Bsep-expressing Sf9 cell vesicles, indicating that it trans-inhibits Bsep only after its secretion into bile canaliculi by Mrp2.

CONCLUSIONS

These results provide a molecular basis for previous in vivo observations and identify Bsep as an important target for induction of drug- and estrogen-induced cholestasis in mammalian liver.

Drug- and chemical-induced cholestasis

Cholestasis resulting from drugs is an increasingly recognized cause of liver disease. It produces a broad clinical-pathologic spectrum of injury that includes simple jaundice, cholestatic hepatitis, and bile duct injury that can mimic extrahepatic biliary obstruction, primary biliary cirrhosis, and sclerosing cholangitis. Although the risk of drug-induced cholestasis leading to a fatal outcome is quite rare, knowledge and recognition of the various forms of cholestatic injury assumes an importance whenever clinicians are confronted with jaundice or other manifestations of liver disease in patients receiving medicinal or chemical agents.

Nonsteroidal anti-inflammatory drug-associated toxicity of the liver, lower gastrointestinal tract, and esophagus

Although upper gastrointestinal (GI) adverse events are the most common consequences of nonsteroidal anti-inflammatory drug (NSAID) use, there are other GI side effects that can contribute to the morbidity and mortality associated with these drugs. NSAID-associated toxicity of the large and small bowel is increasingly recognized in clinical practice, as enteroscopic procedures become more frequently used. This lower GI toxicity may have several different manifestations: ulcerations, strictures, colitis, or exacerbation of inflammatory bowel disease. Hepatic injury, most likely due to an idiosyncratic reaction resulting from an immunologic response or altered metabolic pathways, is another sequela of NSAID use that is usually reversible. Although hepatotoxicity is listed as a class warning for NSAIDs, aspirin, diclofenac, and sulindac are most commonly associated with this problem. Surveillance for hepatic injury is not always reliable, and the low frequency of both hepatic and lower GI toxicity in NSAID users renders these events difficult to characterize. An increase in awareness, surveillance, and reporting of these events can lead to a better understanding of the risk factors and etiology associated with NSAID toxicity.

Mefloquine effect on disposition of halofantrine in the isolated perfused rat liver

Halofantrine and mefloquine are antimalarial drugs used in the treatment of malaria, including that caused by chloroquine-resistant Plasmodium falciparum. Reports of drug-associated adverse reactions, including sudden death in one patient, have prompted concerns over the safety of halofantrine and the potential for drug-drug interactions. We used the isolated perfused rat liver (IPRL) model to investigate a possible hepatic metabolic or pharmacokinetic drug-drug interaction between halofantrine and mefloquine. Pharmacokinetic parameter estimates for halofantrine in the IPRL reflected the pattern seen in in-vivo studies with doses comparable with clinical doses. Halofantrine parameter estimates (mean +/- s.d.) were: volume of distribution (Vd), 7.53 +/- 1.45 mL (g liver)-1; clearance (CL), 0.11 +/- 0.07 mL min-1 (g liver)-1; initial distribution half-life (initial t1/2), 14.62 +/- 2.38 min; terminal half-life (terminal t1/2), 138.7 +/- 178.8 min; AUC 606 +/- 194 mg mL-1 min-1 (g liver)-1; elimination rate constant (Ke), 0.0135 +/- 0.012 min-1. Prior dosing with mefloquine did not affect halofantrine perfusate pharmacokinetic parameter estimates of Vd, Ke, initial and terminal t1/2 (P > 0.05). A single dose, short term (4-6 h) interaction showed significant changes in the perfusate clearance of halofantrine in mefloquine-pretreated livers using higher doses of halofantrine. Substantial changes were seen in bile production (P < 0.05) and biliary clearance (P < 0.05) of halofantrine in mefloquine-pretreated livers. These findings may have clinical implications in models utilizing multiple drug dosages or in patients with severe malaria who have disease-related cholestasis.

[Drug-induced hepatitis: epidemiologic, clinical, diagnostic and physiopathologic aspects in 1995]

Drug-induced hepatotoxicity is a major cause of iatrogenic diseases. More than 900 compounds, including herbal medicines are involved and can reproduce the full spectrum of liver injuries. Acute hepatitis are the most frequently observed. Three types are described: acute hepatocellular hepatitis which are frequently similar to viral hepatitis, and can lead to fulminant liver failure and death within a few days, or, more insidiously, to cirrhosis; acute cholestatic hepatitis, which exhibits a better prognosis, may be misleading by mimicking biliary obstruction; mixed-pattern hepatitis, which associates features of hepatocellular and cholestatic hepatitis. Acute hepatitis generally exhibits no specific patterns. Then, the diagnosis is difficult and relies upon the elimination of other causes and a compatible or a suggestive time-relationship between drug ingestion and the onset of hepatitis as well as between drug withdrawal and recovery. Sometimes, drug hepatotoxicity is suggested by the association of hepatitis to hypersensitivity manifestations (hypereosinophilia), to some histopathological features (eosinophilic infiltration, microvesicular steatosis, giant hepatocytes) or, more uncommonly, to specific autoantibodies (anti-mitochondrial type 6, anti-LKM2, anti-LM antibodies). Cross hepatotoxicity may occur between drugs having related chemical structures.

Risk factors for the development of amoxycillin-clavulanic acid associated jaundice

OBJECTIVES

To identify risk factors for the development of amoxycillin-clavulanic acid associated jaundice.

DESIGN

Retrospective case-control study. Cases were selected from those reported to the Adverse Drug Reactions Advisory Committee from the time of introduction of amoxycillin-clavulanic acid to Australia in 1986 until December 1993.

SUBJECTS

Thirty-four cases, defined as individuals who developed jaundice within eight weeks of starting amoxycillin-clavulanic acid, with a biochemical picture of cholestasis, normal calibre bile ducts and no other recognised causes of jaundice or recent use of other hepatotoxic drugs, were selected. For each case, four controls who had been prescribed amoxycillin-clavulanic acid without developing jaundice were randomly selected from the patient register of the prescribing doctor.

RESULTS

Increasing age was a risk factor for amoxycillin-clavulanic acid associated jaundice; patients over 55 years had an odds ratio of 16.1 (95% confidence interval [CI], 2.9-88.9) compared with patients less than 30 years. Men had an odds ratio of 2.5 (95% CI, 1.1-5.4) compared with women, although the proportion of men in the study group was larger than in the reported cases overall. History of serious medical illness, drug dose, route and duration of therapy, other medications, smoking and previous drug allergies or use of amoxycillin-clavulanic acid were not significantly associated with jaundice.

CONCLUSIONS

Because of the higher risk of jaundice with increasing age, the risk-benefit ratio of amoxycillin-clavulanic acid should be carefully considered in older patients. Further assessment is necessary to clarify the association between jaundice and male sex.

Incidence of liver toxicity associated with the use of flutamide in prostate cancer patients

PURPOSE

The incidence of flutamide-related liver toxicity was studied in 1,091 consecutive patients treated for stage C or D prostate cancer with the antiandrogen flutamide and the luteinizing hormone-releasing factor (LHRH) agonist [D-Trp6, des-Gly-NH2(10)] LHRH ethylamide.

PATIENTS AND METHODS

Liver function tests, namely measurement of serum aspartate amino-transferase (AST) and alanine aminotransferase (ALT), total bilirubin, alkaline phosphatase, gamma-glutamyl transpeptidase (gamma-GT), and prothrombin and thromboplastin times, were performed at 4, 8, and 12 weeks and every 3 months thereafter. Clinical signs and symptoms of liver dysfunction were also sought. The causal link between the antiandrogen used and liver injury was assessed on the basis of the temporal relationship with the use of the drug in the absence of other possible causes and, in two patients, through rechallenge of the putative causative drug after a period of normalization of liver function.

RESULTS

An increase in AST and ALT at fourfold or more above upper normal limits was observed in only four patients (0.36%). Total serum bilirubin and alkaline phosphatase were elevated in only one patient at 126 mmol/L and 640 IU/L, respectively. Among the four patients, only two developed clinical manifestations of liver disease (0.18%). Biopsy was performed in one patient, and the histopathologic findings showed a mixed pattern of cytotoxic and cholestatic changes. All clinical and biologic manifestations of liver toxicity rapidly disappeared upon discontinuation of flutamide alone. No sequelae were observed in the long-term follow-up at 18, 22, 31, and 62 months. The 1,087 remaining patients experienced no or mild (less than fourfold upper normal limit) and transient elevation in aminotransferase serum levels during the first 6 months of treatment, with normalization at later time intervals.

CONCLUSION

Despite the fact that the cases reported so far, along with our large series, indicate that the incidence of flutamide-induced liver toxicity is very low, we recommend serial blood aminotransferase measurements at 2 and 4 weeks of treatment in order to detect early signs of possible flutamide-induced hepatic injury, thus avoiding the low potential risk of clinically significant liver toxicity.

Protracted cholestasis probably induced by oral contraceptive

The case of a patient with intrahepatic cholestasis, probably induced by an oral contraceptive agent, is reported. Initially, early primary biliary cirrhosis was suspected, but this diagnosis could not be verified either clinically or by immunological tests. Re-examination and re-evaluation of the liver biopsy revealed some eosinophilia and sinusoidal dilatation, changes indicative of drug-induced liver injury. The cholestasis gradually disappeared as indicated both biochemically and histologically, but the elevation of serum alkaline phosphatase levels persisted for some 10 years after termination of drug therapy. Oral contraceptive agent-induced jaundice or cholestasis is generally reported to disappear when the drug is stopped, and we are unaware of similar cases in the literature with a protracted course such as that described here. Still, the circumstances of this patient suggest that a correlation between the oral contraceptive agent and the hepatic reaction is most likely, and we consider it important that colleagues pay attention to this possibility.

Antiarrhythmic drugs impair hepatic uptake and secretory function by different mechanisms in the isolated perfused rat liver

In the present study the effect of various antiarrhythmic drugs on hepatic perfusion parameters, uptake capacity of organic anions and biliary secretion using the isolated perfused rat liver was examined. Infusion of verapamil (VP), diltiazem, N-propyl-ajmaline (NPAB), and quinidine at pharmacological doses induced consistently a 1.4-1.6-fold increase in portal pressure accompanied by a approximately 60% decrease in bile flow and a approximately 65% inhibition of biliary taurocholate (TC) excretion. Furthermore, hepatic uptake of oxygen, bromosulphthalein (BSP), and TC was significantly reduced. All these effects were dose-dependent and reversible upon withdrawal of the drugs. Studies of the hepatic circulation using a Trypan blue staining technique demonstrated a patchy perfusion pattern during infusion of the antiarrhythmic drugs as compared to the homogenously stained control organ. The hemodynamic alterations and the impairment of the hepatic initial uptake function could be entirely prevented by concomitant administration of the vasodilator papaverine. Bile flow and biliary TC excretion, however, were still inhibited under these conditions. The present results indicate that antiarrhythmic drugs produce cholestasis in the isolated perfused rat liver independently of their adverse effect on hepatic hemodynamics.

Chemical-induced interference with hepatocellular transport. Role in cholestasis

Transport of endogenous chemicals both into (at the basolateral membrane) and out of (at the canalicular membrane) hepatocytes plays an important role in bile formation. Hence, interference with these processes, for example by chemicals, may result in reduced bile output. Several different systems are available for the study of transport and hence chemicals that may interfere with the process. These have been used to varying degrees with isolated hepatocytes probably being the most popular over recent years. It is likely that hepatocyte couplets and highly purified plasma membrane vesicles will be increasingly employed over the ensuing years. The inhibitory effects of several chemicals on the transport of bile acids have been demonstrated with indications that this may help to account for some aspects of chemical-induced hepatobiliary dysfunction. For example, the inhibition of transport of bile acids by cyclosporin A is consistent with the reported pattern of liver dysfunction in patients on high doses of this immunosuppressant. Investigation into chemical-induced interference with electrolyte transport has yet to receive the same degree of attention. This and other aspects have been suggested as deserving of and likely to be subjected to more intensive experimentation over the next few years.

Cholestatic hepatitis due to an amoxycillin/clavulanic acid preparation

Two cases of reversible cholestatic hepatitis after treatment with an amoxycillin/clavulanic acid preparation (Augmentin) are described.

Drug-induced liver disease

The relative importance of drug-induced liver disease assumes much significance in certain groups of patients such as the elderly. The majority of cases occur as unexpected reactions to a therapeutic dose of a drug. Factors affecting susceptibility to drug-induced liver disease are diverse and are discussed in this article.

Drug-induced jaundice

A large number of drugs may be associated with impaired bile flow. Drug-associated cholestasis presents like other forms of cholestasis with pale stools, dark urine, pruritus and jaundice. Abdominal pain may be present in some instances and can be so severe as to lead to a false diagnosis of acute cholecystitis. Biochemically, drug-associated cholestasis resembles other forms of cholestasis although the presence of eosinophilia may suggest drug involvement. Many types of drug-induced cholestasis run a benign course with resolution of signs and symptoms within 3 months but occasionally the jaundice can take a year or more to resolve. Progression to cirrhosis is uncommon. Some patients may develop a syndrome resembling primary biliary cirrhosis. The mechanisms of drug-associated cholestasis are uncertain but may arise from alteration of bile formation within the hepatocyte or bile excretion at the level of the canaliculus or the extrahepatic ducts. Histological examination of the liver may be helpful in classifying the types of jaundice but the diagnosis of drug-induced cholestasis is usually one of temporal association and exclusion of other causes.

Amoxicillin-clavulanate potassium-associated cholestasis

Amoxicillin-clavulanate potassium, a semisynthetic penicillin-beta-lactamase inhibitor combination drug, is a widely used oral antibiotic. Since the marketing of this drug in 1984, more than nine million prescriptions have been dispensed. Several cases of jaundice and hepatic dysfunction have been observed and reported to the Food and Drug Administration and the pharmaceutical company (Beecham Laboratories). A review of 18 of these cases revealed a predominantly cholestatic syndrome in 7 cases, a mixed hepatocellular-cholestatic picture in 6 cases, a hepatocellular pattern in 4, and in 1 case the injury could not be clearly defined. No fatalities were observed, and all cases had reversal of hepatic dysfunction upon cessation of the drug. Fever was present in 2 patients and eosinophilia in 6 of 10 patients tested, suggesting a hypersensitivity phenomenon contributing to hepatic dysfunction in some of the cases. A percutaneous liver biopsy had been performed in 7 of 18 patients and four of these were reviewed by the authors. Prominent centrizonal cholestasis was seen in all four biopsies. Additionally, 1 patient had periportal and another had midzonal cholestasis. Although infrequent, recognition of an often benign cholestatic syndrome associated with amoxicillin-clavulanate potassium will help avoid unnecessary, invasive, and expensive diagnostic studies and also ameliorate symptoms upon withdrawal of the drug.

Drug-induced jaundice. An uncommon but puzzling reaction

Drug-induced jaundice is relatively uncommon but can be a diagnostic puzzle. Because so many pharmaceutical classes and individual agents can produce jaundice, a thorough history of medications taken should be obtained from a patient presenting with jaundice. Jaundice usually resolves when the offending agent is discontinued.

Drug-induced cholestasis

Acute, drug-induced hepatocellular cholestasis (either pure or cholestatic hepatitis) is a common manifestation of drug-induced hepatic injury. The drugs most frequently responsible are hormonal steroids and psychopharmacological agents (in particular phenothiazines and some antidepressants). Cholestasis usually subsides without sequelae in less than six months. Acute, drug-induced ductular cholestasis is uncommon and can resemble biliary tract obstruction. Complete recovery occurs promptly after the withdrawal of the causative drug in most cases. The pathogenetic mechanism may be immunoallergic. Prolonged ductular or ductal cholestasis can follow drug-induced acute hepatitis despite prompt withdrawal of the offending drug. This syndrome, observed mainly with chlorpromazine and uncommonly with twenty other drugs, is characterized by the progressive disappearance of small bile ducts and by manifestations mimicking primary biliary cirrhosis. However, its prognosis appears to be better than that of primary biliary cirrhosis, the condition being reversible in the majority of cases or even subsiding completely. The mechanism is still unknown, but several features suggest some form of autoimmunity. Extrahepatic cholestasis related to sclerosing cholangitis is a frequent and long-term complication of intra-arterial infusion of floxuridine in patients treated for hepatic metastases from colorectal carcinoma. Although it may be reversible, floxuridine-induced sclerosing cholangitis has a poor prognosis and can lead to death in a few patients. The mechanism is probably related to the vascular supply of the common hepatic duct and its relationship to the perfusion territory of floxuridine.

Aspirin, paracetamol and non-steroidal anti-inflammatory drugs. A comparative review of side effects

Non-steroidal anti-inflammatory drugs (NSAIDs) effectively control the symptoms of many of the rheumatic diseases although they have little effect on the underlying causes. Their effect is mainly on the mediators of the inflammatory process. Unfortunately, these mediators have important physiological roles in the maintenance of health, particularly in the gastrointestinal tract and the kidney, so that their inhibition results in many unwanted reactions of varying severity. The mechanisms underlying these reactions are described. Their occurrence varies, both qualitatively and quantitatively, and an attempt is made to assess these differences, although it may be that they are related directly to differences in dosage and therapeutic efficacy. In addition, immunologically mediated adverse reactions occur. These mechanisms are outlined and related to the clinical picture. There are considerable differences in frequency of reactions between the compounds: in particular there is a wide variation in the rate of dermatological reactions of this type. Agranulocytosis has been particularly associated with the pyrazolone compounds, although it has been reported with most others. Aplastic anaemia, which may not be an immune-mediated reaction, is also thought of as a pyrazolone reaction, but the incidence with indomethacin approaches a similar level. Although all drugs analysed may cause hepatic reactions, these are rare except with the now withdrawn benoxaprofen. Several types of immunologically mediated renal reactions occur and these rarities are also described. Paracetamol does not have any effect on the inflammatory mediators. Anxieties about this substance relates to the parent compound phenacetin and its necrotic effect on the renal papillae. There is extensive literature on this subject concerning not only paracetamol, but also aspirin and other NSAIDs. This is also assessed and summarised. The danger of paracetamol as a direct hepatic toxin in self-poisoning is discussed. Novel NSAIDs are introduced and others withdrawn with frequent and monotonous regularity. Sometimes the reasons have some medical or scientific plausibility, but often they are over-reactions by registration authorities or pharmaceutical companies in response to uninformed media publicity. The problems of the numerically and scientifically accurate collection and assessment of adverse reaction data are legion and as a result useful agents have been lost. Some of these difficulties are described, and some non-drug 'adverse reactions' are described.(ABSTRACT TRUNCATED AT 400 WORDS)